While adding the dataPoints to chart, you need to add labels along with x and y values. Also setting axisX interval according to the dataPoints should work fine in your scenario. Please take a look at this jsfiddle.

Legends are used to represent dataSeries in a chart. You can’t have two legends for one dataSeries. With a workaround, you can display span elements as inactive legends. Please take a look at this updated jsfiddle.